/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:		arm_cmplx_mag_squared_f32.c
*
* Description:	Floating-point complex magnitude squared.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
* ---------------------------------------------------------------------------- */
#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @defgroup cmplx_mag_squared Complex Magnitude Squared
 *
 * Computes the magnitude squared of the elements of a complex data vector.
 *
 * The <code>pSrc</code> points to the source data and
 * <code>pDst</code> points to the where the result should be written.
 * <code>numSamples</code> specifies the number of complex samples
 * in the input array and the data is stored in an interleaved fashion
 * (real, imag, real, imag, ...).
 * The input array has a total of <code>2*numSamples</code> values;
 * the output array has a total of <code>numSamples</code> values.
 *
 * The underlying algorithm is used:
 *
 * <pre>
 * for(n=0; n<numSamples; n++) {
 *     pDst[n] = pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2;
 * }
 * </pre>
 *
 * There are separate functions for floating-point, Q15, and Q31 data types.
 */

/**
 * @addtogroup cmplx_mag_squared
 * @{
 */


/**
 * @brief  Floating-point complex magnitude squared
 * @param[in]  *pSrc points to the complex input vector
 * @param[out]  *pDst points to the real output vector
 * @param[in]  numSamples number of complex samples in the input vector
 * @return none.
 */

void arm_cmplx_mag_squared_f32(
    float32_t* pSrc,
    float32_t* pDst,
    uint32_t numSamples)
{
	float32_t real, imag;                          /* Temporary variables to store real and imaginary values */
	uint32_t blkCnt;                               /* loop counter */

#ifndef ARM_MATH_CM0
	float32_t real1, real2, real3, real4;          /* Temporary variables to hold real values */
	float32_t imag1, imag2, imag3, imag4;          /* Temporary variables to hold imaginary values */
	float32_t mul1, mul2, mul3, mul4;              /* Temporary variables */
	float32_t mul5, mul6, mul7, mul8;              /* Temporary variables */
	float32_t out1, out2, out3, out4;              /* Temporary variables to hold output values */

	/*loop Unrolling */
	blkCnt = numSamples >> 2u;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* C[0] = (A[0] * A[0] + A[1] * A[1]) */
		/* read real input sample from source buffer */
		real1 = pSrc[0];
		/* read imaginary input sample from source buffer */
		imag1 = pSrc[1];

		/* calculate power of real value */
		mul1 = real1 * real1;

		/* read real input sample from source buffer */
		real2 = pSrc[2];

		/* calculate power of imaginary value */
		mul2 = imag1 * imag1;

		/* read imaginary input sample from source buffer */
		imag2 = pSrc[3];

		/* calculate power of real value */
		mul3 = real2 * real2;

		/* read real input sample from source buffer */
		real3 = pSrc[4];

		/* calculate power of imaginary value */
		mul4 = imag2 * imag2;

		/* read imaginary input sample from source buffer */
		imag3 = pSrc[5];

		/* calculate power of real value */
		mul5 = real3 * real3;
		/* calculate power of imaginary value */
		mul6 = imag3 * imag3;

		/* read real input sample from source buffer */
		real4 = pSrc[6];

		/* accumulate real and imaginary powers */
		out1 = mul1 + mul2;

		/* read imaginary input sample from source buffer */
		imag4 = pSrc[7];

		/* accumulate real and imaginary powers */
		out2 = mul3 + mul4;

		/* calculate power of real value */
		mul7 = real4 * real4;
		/* calculate power of imaginary value */
		mul8 = imag4 * imag4;

		/* store output to destination */
		pDst[0] = out1;

		/* accumulate real and imaginary powers */
		out3 = mul5 + mul6;

		/* store output to destination */
		pDst[1] = out2;

		/* accumulate real and imaginary powers */
		out4 = mul7 + mul8;

		/* store output to destination */
		pDst[2] = out3;

		/* increment destination pointer by 8 to process next samples */
		pSrc += 8u;

		/* store output to destination */
		pDst[3] = out4;

		/* increment destination pointer by 4 to process next samples */
		pDst += 4u;

		/* Decrement the loop counter */
		blkCnt--;
	}

	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = numSamples % 0x4u;

#else

	/* Run the below code for Cortex-M0 */

	blkCnt = numSamples;

#endif /* #ifndef ARM_MATH_CM0 */

	while(blkCnt > 0u) {
		/* C[0] = (A[0] * A[0] + A[1] * A[1]) */
		real = *pSrc++;
		imag = *pSrc++;

		/* out = (real * real) + (imag * imag) */
		/* store the result in the destination buffer. */
		*pDst++ = (real * real) + (imag * imag);

		/* Decrement the loop counter */
		blkCnt--;
	}
}

/**
 * @} end of cmplx_mag_squared group
 */
